Tuesday, July 20, 2010

7/20/10: Tuesday's Weather Report

Issued at 3:12 PM CDT, Tuesday, July 20th, 2010

Note: 6th wettest July so far at International Falls, Minnesota. 7.23" of rain has fallen thru July 19th, 2010. The wettest July ever recorded at International Falls happened in 1966 when 9.52" of rain fell.

Here are some rainfall totals across Northern Minnesota from Monday Morning through Tuesday Morning. Source: NWS Duluth, Minnesota.

Hibbing MN: 0.09"

Cass Lake MN: 0.39"

Northome MN: 0.18"

Embarrass MN: 0.37"

Dixon Lake MN: 0.26"

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

A couple of upper level disturbances passing through the Upper Midwest along with a pool of chilly air aloft (500 mb temps around -13 degrees) in conjunction with some surface heating with increasing amounts of instability caused scattered showers and a few thunderstorms around our local area Today. The thunderstorms that have developed This Afternoon have stayed below severe levels, but one cell has turned quite strong as of 3 PM as it heads east-southeast across Northwest Douglas County, just south of the city of Superior in Northwestern Wisconsin. Brief heavy downpours and dangerous lightning strikes have also occurred in a few of these storms This Afternoon. Latest meso-analysis late Today indicates that CAPES have climbed to around 1000 j/kg across Northern Minnesota and Northwest Wisconsin with Lifted Indices ranging from -1/-4 degrees C with Lapse Rates of 6.0-8.0 c/km. 0-6 KM Shear and Effective Bulk Shear was generally around 30-40 knots This Afternoon across our area which is enough to produce an isolated severe weather risk for the rest of Today and into the early Evening hours. Partly-mostly cloudy skies were found in our area Today with high temperatures in the middle 70s to lower 80s with 60s in rain cooled areas and also along the North Shore of Lake Superior. Afternoon dewpoints were in the middle 50s to lower 60s with PWS of 1.00-1.20". Winds Today were variable in direction under 15 mph.

Note: A severe thunderstorm developed and passed through Northern parts of Polk and Barron Counties in Northwest Wisconsin This Afternoon, this storm dropped some very large hail 1.25-2.50" in diameter along with some damaging winds.

Today's Upper Level Analysis:

The flow aloft was nearly zonal Today (west-east) across the Upper Midwest. An upper level disturbance was moving east across Lake Superior and nearby areas of Ontario/Minnesota/Wisconsin This Afternoon per water vapor satellite imagery. An upper level low was centered over Southern Saskatchewan Province This Afternoon per water vapor satellite imagery with movement toward the east. A band of fast mid/upper level winds (50-90 knots) were found across the Northern Plains and Upper Midwest Today to the south-southeast of that upper low in Southern Saskatchewan Province.


Scattered showers or thunderstorms will continue across Northern Minnesota and Northwest Wisconsin This Evening with locally heavy rain and occasional lightning strikes being the main hazards out of these storms along with hail generally under one half inch in diameter and wind gusts up to 40 mph in the stronger storms. Partly-mostly cloudy skies will cover our area Tonight with areas of fog developing Overnight. The threat for showers or thunderstorms should diminish by the late Evening through the Overnight hours the way it looks now. Lows Tonight will be in the 50s to around 60 degrees, perhaps a few 40s in the typical chilly spots if skies clear out enough during the night. Winds will variable under 15 mph.

Wednesday and Wednesday Night:

An area of high pressure will move into the Upper Midwest during this period which should lead to some pleasant conditions. Highs Tomorrow will be in the 70s and 80s with lows Tomorrow Night in the 50s and 60s. Partly-mostly sunny skies are expected Tomorrow with partly-mostly cloudy skies on tap for Wednesday Night. Winds during this period will be out of the west or south up to 20 mph.

Extended Forecast:

South winds will transport a moist airmass north into our area for Thursday and Thursday Night as a rather vigorous disturbance approaches from the Northern Plains while an area of low pressure heads into the Upper Midwest. A stationary front which has been and will continue to be draped across the Central Plains into Wednesday will lift north-northeast Thursday and Thursday Night as the low and disturbance exit the Northern Plains. There will also be a cold front that will head into the Upper Midwest by Thursday Night. The forecast models Today continue to show some disagreement in regards to the track of the low and placement of the warm front on Thursday and this will have implications on how far north the severe weather will get for Thursday and Thursday Night.

Note: The Storm Prediction Center has Northern-Eastern Minnesota and parts of Northwest Wisconsin in a *Slight Risk* for severe thunderstorms Thursday and Thursday Night. The risk area is along and west of a line from Ely to Duluth Minnesota and along and west of a Port Wing to Hayward Wisconsin line.

At this time it looks like the warm front will stay south of our immediate area which means that thunderstorms that form around here should be elevated in nature and could pose a risk for large hail.

Dewpoints climbing into the 60s, PWS of 1.25"-1.75" along with 850 mb td's of +12/+16 degrees C will lead to a heavy rain threat around our area for Thursday and Thursday Night, should thunderstorms develop.

This system looks to pass off to our east on Friday, but a W/NW flow aloft coupled with the possibility of another disturbance or two dropping into the Upper Midwest could lead to a few more showers or thunderstorms Friday and Saturday around Northern Minnesota and Northwest Wisconsin.

High temperatures on Thursday will be in the 70s with lows Thursday Night in the 50s and 60s. Highs on Friday will be in the 70s to lower 80s with lows Friday Night in the 50s and 60s.

5 Day Forecast for Duluth/Superior

.Tonight... A few showers or thunderstorms This Evening. Partly to mostly cloudy. Patchy fog possible late. Low 55 to 60. Wind variable around 12 mph.

.Wednesday... Patchy fog possible early. Partly cloudy. High 78 to 83. Wind west at 10 to 20 mph.

.Wednesday Night... Partly cloudy. Low 57 to 62. Wind becoming south at 5 to 15 mph.

.Thursday... Mostly cloudy. Showers or thunderstorms possible. High 71 to 76. Chance of rain 30%.

.Thursday Night... Mostly cloudy. Showers or thunderstorms possible. Low 58 to 63. Chance of rain 30%.

.Friday... Showers possible. Partly sunny. High 73 to 78. Chance of rain 20%.

.Friday Night... Partly cloudy. Low 55 to 60.

.Saturday... Partly cloudy. Showers or thunderstorms possible. High 78 to 83. Chance of rain 20%.

Normal High Temperature Today 77 degrees

Normal Low Temperature Today 55 degrees